scsi: iscsi: Exclude zero from the endpoint ID range

The kernel returns an endpoint ID as r.ep_connect_ret.handle in the
iscsi_uevent. The iscsid validates a received endpoint ID and treats zero
as an error. The commit referenced in the fixes line changed the endpoint
ID range, and zero is always assigned to the first endpoint ID.  So, the
first attempt to create a new iSER connection always fails.

Link: https://lore.kernel.org/r/20220613123854.55073-1-sergeygo@nvidia.com
Fixes: 3c6ae371 ("scsi: iscsi: Release endpoint ID when its freed")
Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Sergey Gorenko <sergeygo@nvidia.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/scsi_transport_iscsi.c

@@ -212,7 +212,12 @@ iscsi_create_endpoint(int dd_size)
 		return NULL;
 
 	mutex_lock(&iscsi_ep_idr_mutex);
-	id = idr_alloc(&iscsi_ep_idr, ep, 0, -1, GFP_NOIO);
+
+	/*
+	 * First endpoint id should be 1 to comply with user space
+	 * applications (iscsid).
+	 */
+	id = idr_alloc(&iscsi_ep_idr, ep, 1, -1, GFP_NOIO);
 	if (id < 0) {
 		mutex_unlock(&iscsi_ep_idr_mutex);
 		printk(KERN_ERR "Could not allocate endpoint ID. Error %d.\n",